1. Field of the Invention
The invention relates to automatic product weighing machines, particularly for food products, and is also applicable to a range of products, such as fruit, vegetables and the like for instance, and all types and kinds of variously sized items, which are subsequently to be packed with a pre-set total weight and tolerance.
2. Background of the Invention
The inventor/assignee is the holder of U.S. Pat. No. 5,317,110 covering improvements in automatic weighing machines for food products, of the kind comprising a housing for the machine parts, means driving such parts, means feeding the respective products at the machine inlet, commanded by a programming and processing unit, that normally comprise a hopper, a channel and at least an endless belt, the end of which belt leads into an area having receiving buckets flowing beneath it, which buckets are open at the top to receive the products delivered from said end of the endless belt, means for weighing the products contained in each bucket and finding its tare, the buckets having means for unloading the products onto means conveying said products towards the machine outlet, and a programming and processing unit recording the tare of each bucket and the true weight of the products that are collected in each of the buckets as they are weighed, and when the total weight of the products contained in respective buckets reaches a value and tolerance pre-set by the machine user, the programming and processing unit orders the buckets whose product units altogether add up to said total pre-set weight to unload, linking means being provided between said programming and processing unit and the appropriate machine parts, as well as conventional machine command, control and safety means.
These improvements are characterised in that the buckets, lying in a circular and overhanging arrangement, are radially joined by suitable means to a central support turning about a central vertical axis, in that each bucket is joined to the central support by means of two resilient horizontal, parallel and overlying straps which allow the bucket to move up and down, in that the buckets successively pass over a station having a single weighing means, linking up with a programming and processing unit, and in that at least one of the walls of said buckets is mobile, driven by suitable means and commanded by the programming and processing unit to selectively unload each set of product units contained in the respective buckets selected in accordance with the desired total weight, unloading onto means conveying each of said sets of products towards the machine outlet.
The products not selected to be unloaded from the buckets remain contained therein for a new selection in the following cycle.
The strategy of a machine of the type described above is of the kind known as xe2x80x9cassociative weighingxe2x80x9d, in which the products pass by weighing means and an electronic calculator seeks a combination yielding a total real value closest to the desired nominal weight, having the pre-set tolerance.
There is however a need in the market for weighing machines capable of simultaneously obtaining sets of products having a different weight or different sizes, and affording a greater production of said sets per unit of time.
In order to satisfy the market needs, the applicants have devised improvements in automatic product weighing machines of the type of machine subject of U.S. Pat. No. 5,317,110.
The improvements subject of the present invention are applied to automatic product weighing machines, particularly for food products, of the kind comprising a housing for the machine parts, means driving such parts, means feeding the products leading into an area beneath which there is a gradual flow of circularly arranged buckets, having at least a mobile wall and receiving the products delivered, which buckets have respective driving means for unloading the same and are joined to resilient, radial supporting means which are fixed and capable of moving up and down on a support that turns about a central vertical shaft, means for weighing the products contained in the buckets and for obtaining their tare, the buckets having means to selectively unload onto means conveying the products towards the machine outlet, a programming and processing unit that records the tare of every bucket and the true weight of the product or products collected by the buckets and, when the total weight of the products contained in a combination of buckets reaches a value and tolerance pre-set by the machine user, the processing unit orders said buckets to unload through the respective driving means, and means linking said processing unit and the respective machine parts, as well as machine command, control and safety means.
These improvements in automatic product weighing machines, particularly for food products, are characterised in that the buckets are arranged in two series in two concentric circumferences on a same horizontal general plane; that horizontal radially arranged frames are comprised, each having an intermediate cross-member defining two openings, within each of which a bucket of each of the two bucket series is loosely housed, each bucket having the end of a pair of flexible, resilient, overlying and parallel straps joined at each of two of its sides, the other end of the two pairs of straps being joined to the respective frame; that two weighing means are provided, radially aligned in order to simultaneously weigh every pair of buckets in each of the two bucket series and respectively arranged at the weighing area beneath said two series; that the frames have roller means at their free end, standing on a track sector extending from at least the bucket load area to the bucket weighing area, and on another track sector at least located roughly at a position diametrically opposite the weighing area; that the buckets each have roller means at each of their right and left sides, which means each stand on parallel tracks located at the weighing area, connected to the respective weighing means and causing the buckets to be lifted from their frame; that a control is provided for metering the products to be delivered onto the buckets, consisting of two parallel conveyor means over which laminar means may be arranged, individually governed by respective means for the same to be moved in accordance with the respective surfaces to be covered; and that two conveyor means are provided for the products unloaded from the buckets, arranged in a position diametrically opposite and below the same.
The automatic product weighing machine, particularly for food products, provided with the improvements subject of the invention, provides the following advantages, inter alia: the combinations defining the sets of product units with a pre-set weight and tolerance are more speedily obtained; production of said sets per unit of time is increased; the machine is versatile, since it may have several packagers coupled to it in accordance with the user needs; sets of products with a different weight or different sizes may be simultaneously obtained through different outlets from the weighing machine; and an optimum stabilisation of the full or empty buckets at the weighing area, thereby ensuring an accurate weighing.
The improvements of the invention yield the advantages described hereinbefore, and others that will be easily inferred from the example of an embodiment of an automatic product weighing machine, particularly for food products, provided with the above improvements, described hereinafter to facilitate the understanding of the characteristics set out above, and concurrently revealing several details thereof, a number of drawings being therefore attached which represent, for purely illustrative purposes and not to limit the scope of the invention, a practical embodiment thereof.